Process for inhibiting metallic corrosion in aqueous systems

ABSTRACT

The use of a new class of polymeric corrosion inhibiting compositions incorporating pendant heterocyclic groups is disclosed. The polymers form a protective barrier on metallic components to aqueous systems and remain substantive on metallic surfaces over a wide pH range. Moreover, the polymers are resistant to oxidizing biocides, and are substantially impervious to repeated or prolonged exposure to corrosive agents.

[0001] The present invention relates to a process for inhibitingcorrosion of metallic components in contact with aqueous and non-aqueoussystems. More particularly, the invention is directed to introducingoligomeric and polymeric compositions as fluid additives in aqueoussystems that are effective corrosion inhibitors over a wide range of pHand render metals passive to repeated attack by oxidants and oxidizingbiocides. In addition, the invention relates to a process for applyinganti-corrosive coatings to metallic components.

[0002] Metallic components used in industrial processes and heatingventilation and air conditioning (HVAC) operations that are in contactwith fluid media such as, for example, cooling water experience threemajor problems: metal corrosion, deposition of solids and the growth ofmicroorganisms. The three problems are interrelated in that the abilityto control one problem often influences the ability to effectivelycontrol the remaining problems. The most common method to address theproblems is to add a combination of chemical agents and corrosioninhibitors to the fluid media in contact with the metallic components.Polymeric dispersants and phosphonates are commonly used to inhibit thedeposit of solids referred to as scale. Biocidal compositions, inparticular oxidizing biocides such as chlorine or bromine, are oftenused to control the deposition and growth of microorganisms. The mostchallenging problem in the development of new anti-corrosivecompositions is providing effective chemical agents which inhibitcorrosion and which do not produce an adverse environmental impactthemselves or upon treatment with oxidizing biocides.

[0003] Corrosion may be defined as the gradual weight loss of a metalliccomponent through some chemical process or series of chemical reactions.Metals in contact with aqueous systems such as sea water, fresh waterand brackish water and exposed to oxidants contained therein such aschlorine, acid, bleach, caustic and dissolved oxygen are prone tocorrosion. Metal alloys using more corrosion resistant metals (e.g. Ti,Cr, Ni) are one means of improving corrosion resistance. However, suchalloys are costly, difficult to process and manufacture, and experienceproblems with corrosion at joints, welds, and under repeated exposure tocorrosive agents. Inorganic compositions such as chromates, phosphatesor zinc compositions and organic compositions such as tolyltriazole(TTA) and benzotriazole (BZT) are corrosion inhibitors applied to metalsor added to fluids in contact with metallic components which inhibit orslow down the rate of metal corrosion. Azoles, for example, are filmforming compositions that adsorb to metallic surfaces and provide abarrier to contact with an aqueous system. The effectiveness of aparticular composition is usually a trade off of its anti-corrosionproperties as compared to its inherent limitations such as cost, longterm performance and environmental impact. Since metal corrosion occursunder a variety of environmental conditions, specific inhibitorcompositions have been developed to provide corrosion resistance forspecific situations.

[0004] A common corrosion inhibitor for metals such as copper and itsalloys are film forming azoles such as tolyltriazole (TTA) andbenzotriazole (BZT). TTA has been usefully employed as a corrosioninhibitor for metallic components manufactured from copper and copperalloys. When such metals, protected with TTA films, are exposed tooxidizing biocides such as chlorine, however, the corrosion protectionbreaks down. After film breakdown, it is difficult to form newprotective films in TTA treated aqueous systems that are periodically orcontinuously chlorinated. Very high dosages of TTA are frequentlyapplied in an attempt to improve performance, often with limitedsuccess. Other problems associated with combining triazoles andoxidizing biocides in aqueous systems include by-products that are lesseffective corrosion inhibitors, by products which are volatile and thathave objectionable odors and halogen containing by products that aretoxic to the environment if released from the aqueous system. Moreover,it is believed that the decomposition product of TTA may be more toxicthan TTA, which itself is toxic to fish populations. Under theconditions found in cooling water treatment equipment, the decompositionproduct of TTA is believed to be an N-chlorinated compound, which isrelatively volatile and susceptible to removal by stripping in thecooling tower, further reducing the levels of corrosion inhibitor andoxidizing biocide in the system.

[0005] When copper containing metals corrode, excessive concentrationsof copper are released and subsequently discharged in to rivers thatoften serve as reservoirs of cooling water. The toxic effects of copperon fish populations and other organisms in aqueous ecosystems is wellestablished. In addition, excessive concentrations of copper ions canredeposit on mild steel components, setting up a galvanicoxidation-reduction couple leading to severe metal pitting.

[0006] U.S. Pat. No. 5,863,464 discloses a method of inhibitingcorrosion in aqueous systems using halogen containing benzotriazoles ascorrosion inhibitors. However, halogen containing azoles released fromthe aqueous system are toxic to fish populations and other biologicalspecies. Another problems is the inherent corrosive nature of halogencontaining azoles in contact with metallic surfaces. Different triazolesprovide varying levels of protection to the metallic surfaces fromdirect halogen attack based on factors such as film hydrophobicity,triazole structure, packing density and film thickness. Accordingly, itwould be desirable to provide alternative methods of inhibiting metalliccorrosion in aqueous systems that incorporate corrosion inhibitors thatare effective over a wide range of pH, that are resistant to oxidizingbiocides and that have minimal environmental impact.

[0007] The inventors recognized a need to provide corrosion inhibitingcompositions having substantive film forming ability that are effectiveover a wide pH range in aqueous or non-aqueous systems, that areresistant to oxidizing biocides and that can withstand repeated andprolonged chemical attack by corrosive agents such as chlorine. Theinventors discovered a new class of polymeric corrosion inhibitingcompositions incorporating pendant heterocyclic groups which aresurprisingly effective copper corrosion inhibitors and remainsubstantive on metallic surfaces over a wide pH range in aqueous andnon-aqueous systems, are resistant to oxidizing biocides, and aresubstantially impervious to repeated or prolonged exposure to corrosiveagents.

[0008] The present invention provides a process for inhibiting corrosionof metallic components in contact with an aqueous system comprising thestep of adding to the system an effective amount of one or more polymerscomprising at least one repeating unit selected from a functionalizedimide component of Formula Ia, a functionalized amide component ofFormula Ib and combinations of Formulas Ia and Ib:

[0009] wherein n is 0 or 1; R and R₁ are independently selected fromhydrogen, methyl, and C₂-C₄ alkyl; R₂ is selected from C₁-C₈ branchedand straight chain alkyl groups, C₂-C₈ branched and straight chainalkenyl groups, C₃-C₈ cyclic alkyl groups, C₆-C₁₀ unsaturated acyclic,cyclic and aromatic groups, C₂-C₄ alkylene oxide groups and poly(C₂-C₄alkylene)m oxides, wherein m=2-20; a pendant heterocycle which comprisesunsaturated or aromatic heterocycles having one or more hetero atomsselected from N, O, S and combinations thereof, the pendant heterocyclechemically bonded to R₂ via a hetero atom which is part of the pendantheterocycle or a carbon atom of the pendant heterocycle; R₃ is selectedfrom hydrogen, methyl, ethyl, C₃-C₁₈ branched and straight chain, alkyland alkenyl groups; and R₄ is selected from H, CH₃, C₂H₅, C₆H₅ andC₃-C₁₈ branched or straight chain alkyl and alkenyl groups.

[0010] Accordingly, the present invention provides a process forinhibiting corrosion of metallic components in contact with an aqueoussystem comprising the step of adding to the system an effective amountof corrosion inhibiting polymer comprising:

[0011] i) at least one repeating unit selected from a functionalizedimide component of Formula Ia, a functionalized amide component ofFormula Ib and combinations of Ia and Ib;

[0012] ii) at least one ethylenically unsaturated monomer componentselected from maleic anhydride, itaconic anhydride, cyclohex-4-enyltetrahydrophthalic anhydride, and monomers of Formula II:

[0013] Formula II

CH(R5)=C(R6)(R7)

[0014] wherein R₅ is selected from hydrogen, phenyl, methyl, ethyl,C₃-C₁₈ branched and straight chain alkyl and alkenyl groups; R₆ isindependently selected from hydrogen, methyl, ethyl, phenyl, C₃-C₁₈branched and straight chain alkyl and alkenyl groups, OR₈ and CH₂OR₈groups wherein R₈ is acetate, glycidyl, methyl, ethyl, C₃-C₁₈ branchedand straight chain alkyl and alkenyl groups, and groups having theformula [CH₂CH(R_(a))O]_(m)R_(b) wherein R_(a) is hydrogen, methyl,ethyl, and phenyl, m is an integer from 1-20 and R_(b) is independentlyhydrogen, methyl, ethyl, phenyl and benzyl; and R₇ is independentlyselected from H, CH₃, C₂H₅, CN, a COR₉ group wherein R₉ is OH, NH₂, OR₈group wherein R₈ is a group described previously and a NR_(c)R_(d) groupwherein R_(c) and R_(d) are the same group or different groups, areparts of a 5-membered or 6-membered ring system, hydrogen,hydroxymethyl, methoxy methyl, ethyl and C₃-C₁₈ branched and straightchain alkyl and alkenyl groups branched and straight chain alkyl andalkenyl groups; and

[0015] optionally one or more end groups selected from initiatorfragments, chain transfer fragments, solvent fragments and combinationsthereof.

[0016] Alternatively, the present invention provides a process forinhibiting corrosion of metallic components in contact with an aqueoussystem comprising the step of adding to the system an effective amountof corrosion inhibiting polymer of formula III:

[0017] Formula III

(A)x(B)y(C)z

[0018] wherein A is an optional end group component selected frominitiator fragments, chain transfer fragments, solvent fragments andcombinations thereof; wherein B is a functionalized imide component ofFormula Ia, a functionalized amide component of Formula Ib andcombinations of Ia and Ib; wherein C is an ethylenically unsaturatedmonomer component selected from maleic anhydride, itaconic anhydride,cyclohex-4-enyl tetrahydrophthalic anhydride, and monomers of FormulaII; and wherein x, y, z are integers values chosen such that (y+z)/x isgreater than 2.

[0019] The present invention also provides a process for inhibitingcorrosion of metallic components in contact with an aqueous systemcomprising the step of adding to the system an effective amount of oneor more polymers of Formula III:

[0020] Formula III

(A)x(B)y(C)z

[0021] wherein A is an end group component selected from initiatorfragments, chain transfer fragments, solvent fragments and combinationsthereof; wherein B is a functionalized imide component of Formula Ia, afunctionalized amide component of Formula Ib and combinations of Ia andIb; wherein C is an ethylenically unsaturated monomer component selectedfrom maleic anhydride, itaconic anhydride, cyclohex-4-enyltetrahydrophthalic anhydride, and monomers of Formula II; and wherein x,y, z are integers values chosen such that (y+z)/x is greater than 2.

[0022] The present invention also provides a process for inhibitingcorrosion of metallic components in contact with an aqueous systemcomprising the step of adding to the system an effective amount of oneor more polymers comprising:

[0023] i) one or more end groups selected from initiator fragments,chain transfer fragments, solvent fragments and combinations thereof;

[0024] ii) at least one repeating unit selected from a functionalizedimide component of Formula Ia, a functionalized amide component ofFormula Ib and combinations of Ia and Ib; and

[0025] iii) at least one unit selected from a functionalized imidecomponent or a functionalized amide component selected from succinimide,glutarimide and combinations thereof, wherein the nitrogen atom of eachcomponent of B′ is chemically bonded to a group selected from C₁-C₁₈branched or straight chain alkyl, C₁-C₁₈ alkyl or alkenyl substitutedaryl, which is in turn chemically bonded to a pendant functional groupselected from an amine group, amide group, carboxylic acid group,alcohol group or a group having the formula [CH₂CH(R_(a))O]_(m)R_(b)wherein R_(a) is hydrogen, methyl, ethyl, and phenyl, m is an integerfrom 2-20 and R_(b) is independently hydrogen, methyl, ethyl, phenyl andbenzyl.

[0026] Alternatively, the present invention also provides a process forinhibiting corrosion of metallic components in contact with an aqueoussystem comprising the step of adding to the system an effective amountof one or more polymers of Formula IV:

[0027] Formula IV

(A)x(B)y(B′)z

[0028] wherein A is an end group selected from initiators fragments,chain transfer fragments, solvent fragments and combinations thereof;wherein B is a functionalized imide component of Formula Ia selectedfrom succinimide, glutarimide and combinations thereof; wherein B′includes at least one unit selected from a functionalized imidecomponent or a functionalized amide component selected from succinimide,glutarimide and combinations thereof, wherein the nitrogen atom of eachcomponent of B′ is chemically bonded to a group selected from C₁-C₁₈branched or straight chain alkyl, C₁-C₁₈ alkyl or alkenyl substitutedaryl, which is in turn chemically bonded to a pendant functional groupselected from an amine group, amide group, carboxylic acid group,alcohol group or a group having the formula [CH₂CH(R_(a))O]_(m)R_(b)wherein R_(a) is hydrogen, methyl, ethyl, and phenyl, m is an integerfrom 2-20 and R_(b) is independently hydrogen, methyl, ethyl, phenyl andbenzyl; and wherein x, y, z are integers values chosen such that (y+z)/xis greater than 2.

[0029] The present invention also provides a process for inhibitingcorrosion of metallic components in contact with an aqueous systemcomprising the step of adding to the system an effective amount of acorrosion inhibiting formulation including one or more corrosioninhibiting polymer compositions and one or more additives selected fromthe group consisting of biocidal compositions, corrosion inhibitingcompositions different from those of the present invention, scaleinhibiting compositions, dispersants, defoamers, inert tracers andcombinations thereof.

[0030] Accordingly, the present invention provides a process forinhibiting corrosion of metallic components used in the manufacture ofequipment associated with aqueous and non-aqueous systems that requirecorrosion protection. “Aqueous system” refers to any system containingmetallic components which contain or are in contact with aqueous fluidson a periodic or continuous basis. The term “aqueous fluids” refers tofluids containing 5 weight percent or more water and includeswater-based fluids. Water based fluids refer to fluids containing aminimum of 40 percent by weight water, the remainder being suspendedand/or dissolved solids and compounds that are soluble in water.“Non-aqueous system” refers to any system containing metallic componentswhich contain or are in contact with non-aqueous fluids on a periodic orcontinuous basis. Non-aqueous fluids may be miscible or immiscible inwater.

[0031] Typical aqueous systems include, for example, recirculatingcooling units, open recirculating cooling units that utilize evaporationas a source of cooling, closed loop cooling units, heat exchanger units,reactors, equipment used for storing and handling liquids, boilers andrelated steam generating units, radiators, flash evaporating units,refrigeration units, reverse osmosis equipment, gas scrubbing units,blast furnaces, paper and pulp processing equipment, sugar evaporatingunits, steam power plants, geothermal units, nuclear cooling units,water treatment units, food and beverage processing equipment, poolrecirculating units, mining circuits, closed loop heating units,machining fluids used in operations such as for example drilling,boring, milling, reaming, drawing, broaching, turning, cutting, sewing,grinding, thread cutting, shaping, spinning and rolling, hydraulicfluids, cooling fluids, oil production units and drilling fluids.Typical examples of aqueous fluids include fresh water, brackish water,sea water, waste water, mixtures of water and salts (known as brines),mixtures of water and alcohol such as methanol, ethanol and ethyleneglycol, mixtures of water and acids such as mineral acids, mixtures ofwater and bases such as caustic and combinations thereof. Aqueoussystems treated using the compositions of this invention may containdissolved oxygen or may contain no oxygen. The aqueous systems maycontain other dissolved gases such as, for example, carbon dioxide,ammonia and hydrogen sulfide.

[0032] In the descriptions that follow, the terms oligomer, polymer andco-polymer are used. Oligomer refers to compositions produced by thepolymerization of one or more monomer units wherein the number ofmonomer units incorporated in the oligomer are between 2 and about 10.Polymer refers to compositions produced by the polymerization of one ormore monomer units with no restriction on the number of types of monomerunits incorporated in the polymer. Co-polymer refers to compositionsproduced by the polymerization of two different monomer units with norestriction on the number of either monomer units incorporated in theco-polymer.

[0033] The metallic components in contact with the aqueous system areprocessed from any metal for which corrosion and/or scaling can beprevented. Typical examples of metals requiring corrosion protection arecopper, copper alloys, aluminum, aluminum alloys, ferrous metals such asiron, steels such as low carbon steel, chromium steel and stainlesssteel, iron alloys and combinations thereof.

[0034] Different types of metal corrosion are encountered in aqueoussystems such as, for example, uniform corrosion over the entire metalsurface and localized corrosion such as pitting and crevice forming.Often, control of localized corrosion may be the critical factor inprolonging the useful life of the metal components in contact with theaqueous system. Aqueous systems containing significant concentrations(also referred to as “levels”) of anions such as chloride and sulfateare prone to both uniform and localized corrosion. These anions areoften present in the aqueous fluids used in the system. Uniform andlocalized corrosion often result in the failure of the metalliccomponents requiring replacement or extensive repairs and maintenance,both shutting down operation of the aqueous system. Therefore, thepresent invention provides polymeric compositions for inhibitingcorrosion in aqueous systems.

[0035] The corrosion resistant polymer compositions usefully employed inthe present invention are substantially resistant or impervious tooxidizing biocides including for example oxidants such as oxygen, ozoneand hydrogen peroxide, halogens such as chlorine, bromine, and iodine,combinations of oxidants such as NaOCl and alkali salts of Group VII(Group 17 according to the nomenclature of the International Union ofPure and Applied Chemists) elements, organic compounds such ashydantinoids, cyanuric acid derivatives, substituted cyanuric acidderivatives such as chloro cyanuric acid, alkali and alkaline earthsalts of cyanuric acid and cyanuric acid derivatives, and combinationsthereof. In addition, the anti-corrosive compositions are substantiallyresistant or impervious to repeated and prolonged exposure to corrosiveagents including for example chlorine, bromine, and iodine; hypochloriteand its alkali metal salts such as sodium hypochlorite; hypochloricacid; chlorous acid; mineral acids such as hydrochloric acid, sulfuricacid and phosphoric acid; perchloric acid, basic compounds such as lye,caustics, bleaches, and ammonia; reducing agents such as sulfides,sulfites and alkali metal sulfides; and combinations thereof.

[0036] The corrosion inhibiting compositions of the present inventionare effective in highly acidic or basic aqueous systems, namely, at pHbetween 0.5 and 14. It is preferred that the corrosion inhibitingcompositions are added to the aqueous systems at pH between 6 and 10.

[0037] All polymers and corrosion inhibiting polymer compositionsusefully employed in the present invention include at least onerepeating unit selected from a functionalized imide component havingFormula Ia, a functionalized amide component having Formula Ib andcombinations of Formulas Ia and Ib:

[0038] Preferably n is 0. Preferably R and R₁ are hydrogen. PreferablyR₂ is selected from C₂-C₈ branched and straight chain alkyl groups.Preferably, R₃ is selected from C₃-C₁₈ branched and straight chain alkylgroups. Preferably, Preferably, R₄ is selected from C₃-C₁₈ branched andstraight chain alkyl groups.

[0039] Suitable heterocycles usefully employed in accordance with theinvention include for example 5 to 7-membered heterocycles having somedegree of unsaturation, aromatic heterocycles having at least one heteroatom selected from N, O or S atoms, their respective isomers andcombinations thereof. The heterocycle is chemically bonded to the R₂group via a hetero atom which is part of the heterocycle or a carbonatom of the heterocycle. In addition, suitable heterocycles include forexample 5 to 7-membered heterocycles that are fused together to formlarger 9 to 14-membered heterocycles having more than one type orcombination of N, O or S atoms, isomers of such heterocycles andcombinations thereof.

[0040] Preferred heterocyclic groups include for example imidazole,thiophene, pyrrole, oxazole, thiazoles and and their respective isomerssuch as thiazol-4-yl, thiazol-3-yl and thiazol-2-yl, pyrazole,substituted thiazoles and their respective isomers such as 2-aminothiazol-4-yl, tetrazole, pyridine, pyridazine, pyrimidine, pyrazine,azoles, indazoles, triazoles and their respective isomers such as 1, 2,3-triazole, 1,2,4-triazole, and combinations thereof.

[0041] The nitrogen atom constituting the functionalized imidecomponents and functionalized amide components of B further ischemically bonded to a R₂ group, which in turn is chemically bonded toan atom that constitutes the pendant heterocycle. In an embodimentwherein the corrosion inhibiting composition is oligomeric or polymeric,the functionalized imide components and functionalized amide componentsare incorporated in to the backbone of the oligomer or polymer andfurther include a pendant heterocyclic group.

[0042] Preferred R₂ groups include for example C₁-C₈ branched alkylgroups such as isopropyl, isobutyl, isopentyl, neopentyl, isoamyl andisooctyl; C₂-C₈ straight chain alkyl groups such as ethyl, propyl,butyl, pentyl, hexyl, heptyl and octyl, C₂-C₈ branched alkenyl groupssuch as 2-methyl-but-3-enyl; C₁-C₈ straight chain alkenyl groups such asbut-2-enyl and pent-3-enyl; C₇-C₁₀ cyclic unsaturated groups such2-methyl-cyclohex-3-enyl; C₆-C₁₀ aromatic groups such as phenyl, benzyl,tolyl, and tolyl isomers such as methylbenzyl, dimethylbenzyl, xylenyland xylenyl isomers; C₃-C₈ cyclic alkyl such as 2-methyl 1,4-cyclohexyl;poly(C₂-C₄ alkylene) oxide such as poly(ethylene oxide), poly(propyleneoxide), poly(butylene oxide) and mixtures thereof.

[0043] In a separate embodiment, the nitrogen atom constituting thefunctionalized imide components and functionalized amide components ofB′ is chemically bonded to a group selected from C₁-C₁₈ branched orstraight chain alkyl, C₁-C₁₈ alkyl or alkenyl substituted aryl, which isin turn chemically bonded to a pendant functional group selected from anamine group, amide group, carboxylic acid group, alcohol group or agroup having the formula [CH₂CH(R_(a))O]_(m)R_(b) wherein R_(a) ishydrogen, methyl, ethyl, and phenyl, m is an integer from 2-20 and R_(b)is independently hydrogen, methyl, ethyl, phenyl and benzyl. Preferredexamples include C₁-C₂₅ alkyl amines such as butyl amine, hexyl amine,octyl amine, decyl amine, dodecyl amine and stearyl amine; octyl amine;and C₁-C₂₅ alkyl amides such as hexyl amide, n-octyl amide, decyl amideand stearyl amide.

[0044] Accordingly, this invention provides a process for inhibitingcorrosion of metallic components in contact with an aqueous systemcomprising the step of adding to the system an effective amount of acorrosion inhibiting polymer comprising chemical components A, B and C;wherein A optionally includes one or more end groups selected frominitiator fragments, chain transfer fragments, solvent fragments andcombinations thereof; wherein B includes at least one repeating unitselected from a functionalized imide component of Formula Ia, afunctionalized amide component of Formula Ib and combinations of Ia andIb; and wherein C represents at least one ethylenically unsaturatedmonomer component of Formula II. The components A, B and C are arrangedrandomly within the polymer and can be arranged sequentially inaccordance with the invention.

[0045] Component A includes for example any initiator fragment derivedfrom any initiator useful in initiating free radical additionpolymerization. Such initiator fragments include, but are not limitedto, peroxyesters, such as t-butylperbenzoate, t-amylperoxybenzoate,t-butylperoxy-2-ethylhexonate, butylperacatate and t-butylperoxylmaleicacid; dialkylperoxides such as di-t-butylperoxide, dicumylperoxide andt-butylcumylperoxide; diacylperoxides such as benzoylperoxide,lauroylperoxide and acetylperoxide; hydroperoxides such as cumenehydroperoxides and t-butylhydroperoxide; azo compounds such asazonitriles, azaamidines, cyclic azoamidines, alkylazo compounds such asazodi-tert-octane.

[0046] Component A further includes for example end groups resultingfrom any chain transfer agent used in controlling the molecular weightof a free radical polymerization. Suitable chain transfer agents includebut are not limited to alcohols, alkyl and aromatic thiols, alkylphosphites, aryl phosphinic acids, alkyl phosphinic acids,hypophosphites, aldehydes, formates, alkylhalides and alkyl aromaticsuch as toluene, xylenes, and C9-10 alkylaromatics such as Aromatic 100.

[0047] Component B refers to more than one of either a functionalizedimide component or a functionalized amide component having respectiveFormulas Ia and Ib. Preferred B components are selected fromsuccinimide, glutarimide and combinations thereof. The nitrogen atomthat constitute the imide or amide portion of component B must bechemically bonded to at least one atom of a R₂ group which in turn ischemically bonded to a pendant heterocycle. R₂ groups consisting of 2 to8 consecutive atoms between the nitrogen atom of the imide or amideportion of B and the heterocycle are more preferred. R₂ groupsconsisting of 3 to 6 consecutive atoms between the imide or amideportion of B and the heterocycle are most preferred.

[0048] Component C includes ethylenically unsaturated monomers ofFormula III. Examples of suitable monomers include (meth)acrylic acid,methyl (meth)acrylate, hydroxy (meth)acrylate, 2-hydroxyethyl acrylate,2-hydroxy propyl acrylate, butyl (meth)acrylate, 2-ethylhexyl acrylate,decyl acrylate, lauryl (meth)acrylate, isodecyl (meth)acrylate,hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate; cyclicanhydrides such as maleic anhydride; anhydrides such as itaconicanhydride, and cyclohex-4-enyl tetrahydrophthalic anhydride; olefinssuch as ethylene, propylene, butylene, isobutylene, di-isobutylene,d-limonene; olefin oligomers such as propylene tetramer (C₁₂-C₁₄) andpropylene dimer trimer (C₁₈-C₂₂); α-olefins such as 1-butene, 1-octeneand 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene,Gulftene® 20-24, Gulftene® 24-28; styrene, and substituted styrenes suchas α-methyl styrene, α-methylstyrene, 4-hydroxystyrene, styrene sulfonicacid; butadiene; vinyl acetate, vinyl butyrate and other vinyl esters;and vinyl monomers such as vinyl chloride, vinylidene chloride; vinylethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinylether, butyl vinyl ether, isobutyl vinyl ether; allyl ethers such asallyl ether, allyl ethyl ether, allyl butyl ether, allyl gylcidyl ether,allyl carboxy ethyl ether; ethoxy vinyl ethers such asvinyl-2-(2-ethoxy-ethoxy)ethyl ether, methoxyethoxy vinyl ether, vinylacetate, vinyl formamide and vinyl acetamide, stilbene; divinyl benzene;(meth)acrylic monomers such as (meth)acrylate esters, (meth)acrylamides,and (meth)acrylonitrile. The use of the term “(meth)” followed byanother term such as acrylate or acrylamide, as used throughout thedisclosure, refers to both acrylates or acrylamides and methacrylatesand methacrylamides, respectively. Preferred monomers of component Cinclude ethylene, propylene, isobutylene, di-isobutylene, propylenetetramer (C₁₂-C₁₄), and propylene dimer trimer (C₁₈-C₂₂).

[0049] The corrosion inhibiting compositions usefully employed in thepresent invention have weight average molecular weights that range from400 to 20,000. More preferred are compositions having weight averagemolecular weights that range from 400 to 10,000. Most preferred arecompositions having weight average molecular weights that range from 400to 5,000. Weight average molecular weights of the polymeric compositionswere measured by GPC techniques using styrene as a standard.

[0050] Polymers usefully employed according to the invention can beprepared by conventional emulsion, solution or suspensionpolymerization, including those processes disclosed in U.S. Pat. No.4,973,409. Solution polymerization is preferred.

[0051] The polymerization of monomers is performed in a suitable solventand in the presence of an initiator. Suitable solvents include forexample water, dioxane, ketones such as 4-methylbutan-2-one, aromatichydrocarbons such as toluene, xylene and xylene isomers, alcohols suchas methanol and ethanol and ethers such as dioxane. Suitable reactioninitiators include for example azo(bis)isobutyronitrile (AIBN), organicperoxides such as benzoyl peroxide, di-t-butyl peroxide, hydroperoxidessuch as t-butyl hydroperoxide and t-amyl hydroperoxide, hydrogenperoxide, sodium perborate, alkali metal persulfates and ammoniumpersulfate.

[0052] The corrosion inhibiting polymer compositions are easily preparedin two steps. The first step includes for example polymerization of oneor more monomers such as maleic anhydride with one or more ethylenicallyunsaturated monomer units of C such as di-isobutylene. The anhydrideportion of the resulting co-polymer is then converted via one or morepost polymerization functionalization reactions such as condensation,amidation, imidation, or esterification to afford polymer compositionsof Formula Ia or Ib. Alternatively, the compositions are easily preparedby polymerizing one or more functionalized monomer units of B with oneor more ethylenically unsaturated monomer units of C to afford polymercompositions of Formula Ia or Ib.

[0053] The polymer products of either process for the purpose ofisolation may be subjected to partial or complete evaporation underreduced pressure. The unpurified reaction products may be used as thepolymer composition of the present invention. The reaction products mayalso be purified. The pruification procedure consists of: a) evaporationof reaction solvent and washing with a water immiscible organic solventsuch as ether, followed by evaporation of this solvent or b) evaporationof the reaction solvent, dissolving the polymer product in a suitablesolvent and precipitating the polymer with a suitable non-solvent suchas toluene or xylenes.

[0054] Polar groups incorporated in the polymers from the heterocyclicgroups, the end groups and the amide/imide components strongly adsorb tometallic surfaces. The polymeric nature of the compositions coupled withhigh numbers of polar anchoring groups provide effective corrosioninhibition for metals and metal alloys by forming films exhibitingsuperior barrier properties over a broader range of pH, while remainingsubstantially impervious to corrosive agents present in aqueous systemsand maintaining their anti-corrosive effectiveness over repeatedadditions of oxidizing biocides and corrosive agents such as chlorinefor extended time periods.

[0055] The corrosion inhibiting polymer compositions of the inventionhave the following advantages: improved chlorine resistance, lowtoxicity and environmental impact as compared to azoles such as TTA andBZT, a wide range of pH stability, formulated in safe and cost effectivemanner and are detected and monitored at ppm concentrations (alsoreferred to as traceability). Improved chlorine resistance results inlower concentrations of metal ions such Cu²⁺ discharged in to theaqueous system in compliance with EPA regulatory discharge restrictions,reduced galvanic corrosion, increased useful life of metalliccomponents, reduced levels of polymer required for corrosion protectionand elimination of odors associated with azoles. The low toxicity of thepolymer compositions results in a lowered environmental impact asevidenced by relatively lower aquatic toxicological profiles. Thepolymer composition stability in a wide pH range allows for reductionsor elimination of caustic providing reduced handling and shippinghazards. The polymers are made from inexpensive, commercially availablemonomer feedstocks and are easily formulated with other biocides, scaleinhibitors and any other required additives known to be useful intreatment of aqueous systems. The heterocyclic group incorporated in thepolymer provides a means to monitor low concentrations (ppm levels) ofthe polymer in the aqueous system via UV-vis absorption or fluorescencetechniques, also referred to as traceability. An inert fluorescenttracer can also be incorporated in to the polymer as well to determineand monitor static and dynamic levels of the polymer in the aqueoussystem. The traceability of the polymers at ppm levels provides a meansto detect the polymer concentration in the aqueous system and controlthe feed or dose rate required, resulting in significant costperformance. In practice, the amount of polymer compositions of FormulaIa or Ib used to treat the aqueous system varies according to theprotective function required.

[0056] The polymer compositions of the present invention can preferablybe added to the aqueous system at active amounts ranging between 0.1 to50,000 ppm (0.00001 to 5 weight %), preferably from 1 to 500 ppm, mostpreferably from 1 to 100 ppm, based on the weight of the aqueous system.

[0057] The polymer compositions of this invention are used to preparecorrosion inhibiting formulations by combining the polymer with one ormore additives known to be useful in treating aqueous systems such asfor example biocidal compositions, any other corrosion inhibitingcomposition known in the art, scale inhibiting compositions,dispersants, defoamers, inert fluorescent tracers and combinationsthereof.

[0058] To enhance their solubility and compatibility in formulations andfluid media, the corrosion inhibitors of the present invention can beformulated with surfactants, defoamers, co-solvents and hydrotropes ortheir pH can be altered with suitable acids or bases. Examples ofsuitable surfactants include but are not limited to Rhodafac® RS 610 orRhodafac® RE 610 manufactured by Rhodia, Inc. Examples of suitabledefoamers include but are not limited to GE silicone antifoam AF60.Suitable co-solvents include for example ethanol, isopropanol, ethyleneglycol and propylene glycol. Suitable hydrotropes include Monatrope®1250A manufactured by Uniqema, and sodium xylene sulfonate.

[0059] Suitable scale inhibitors include for example polyphosphates andpolycarboxylic acids and copolymers such as described in U.S. Pat. No.4,936,987.

[0060] The corrosion inhibitors of the present invention can also beused with other agents to enhance corrosion inhibition of copper,aluminum, mild steel, alloys of these and other metals. Examples ofthese agents include phosphates or phosphoric acid, polyphosphates suchas tetrapotassium pyrophosphate and sodium hexametaphosphate, zinc,tolyltriazole, benzotriazole and other azoles, molybdate, chromate,phosphonates such as 1-hydroxyethylidene-1,1-diphosphonic acid,aminotris(methylene phosphonic acid), hydroxyphosphonoacetic acid and2-phosphonobutane-1,2,4-tricarboxylic acid, polymeric corrosioninhibitors such as poly(meth)acrylic acid or polymaleic acid andcopolymers of acrylic, methacrylic and maleic acid, as well as theiralkali metal and alkaline earth metal salts.

[0061] In addition, the corrosion inhibitors may also be used with otheragents such as scale inhibitors and dispersants. Examples of theseagents include poly(meth)acrylic acid, polymaleic acid, copolymers ofacrylic, methacrylic or maleic acid, phosphonates as previouslydescribed, and chelants such as nitrilotriacetic acid or ethylenediaminetetraacetic acid, as well as their metal salts. The agents described maybe applied in a single formulation or applied separately.

[0062] The polymer compositions of the invention are usefully employedas fluid additives such as coolants, antifreezes, metal working fluids,lubricants, brake fluids, transmission fluids, aircraft de-icing fluids,fluids for polishing electronic devices (e.g. in chemical mechanicalplanarization (CMP) processes), soldering additives, anti-abrasivecompounds, direct metal treatment fluids, cleaning agents and detergentsfor photographic processes, anti-corrosive coatings, caulks, sealantsand pressure sensitive adhesives in contact with metallic components.

[0063] In a preferred embodiment, corrosion inhibiting compositions areusefully employeded in accordance with the present invention as fluidadditives in contact with metallic components.

[0064] In an alternative embodiment, the corrosion inhibitingcomposition are usefully employed as anti-corrosive coatings bytechniques which are well known in the coatings art. First, if thecomposition is an elastomeric coating, caulk, sealant or pressuresensitive adhesive composition is to be pigmented, at least one pigmentis well dispersed in an aqueous medium under high shear such as isafforded by a COWLES® mixer or, for more viscous compositions such ascaulks and sealants, a high intensity mixer or mill. Then the waterbornepolymer is added under lower shear stirring along with other elastomericcoating, caulk, sealant or pressure sensitive adhesive adjuvants asdesired. Alternatively, the aqueous emulsion polymer may be included inthe pigment dispersion step. The aqueous composition may containconventional elastomeric coating, caulk, sealant or pressure sensitiveadhesive adjuvants such as, for example, tackifiers, pigments,emulsifiers, coalescing agents, buffers, neutralizers, thickeners orrheology modifiers, humectants, wetting agents, biocides, plasticizers,antifoaming agents, colorants, waxes, and anti-oxidants.

[0065] The solids content of the aqueous coating composition may be fromabout 10% to about 85% by volume. The viscosity of the aqueouscomposition may be from 0.05 to 2000 Pa.s (50 cps to 2,000,000 cps), asmeasured using a Brookfield viscometer; the viscosities appropriate fordifferent end uses and application methods vary considerably.

[0066] The oligomeric and polymeric corrosion inhibiting compositionsmay be applied by conventional application methods such as, for example,brushing and spraying methods such as, for example, roll coating,dipping doctor-blade application, printing methods, an aerosol,air-atomized spray, air-assisted spray, airless spray, high volume lowpressure spray, air-assisted airless spray, caulk guns, and trowels.

[0067] In addition to metals, the polymeric corrosion inhibitingcompositions may be applied to substrates including but not limited tofor example, plastic including sheets and films, wood, previouslypainted surfaces, cementitious substrates, asphaltic substrates or thelike, with or without a prior substrate treatment such as an acid etchor corona discharge or a primer.

[0068] The following examples are presented to illustrate the inventionand the results obtained by the test procedures.

[0069] Abbreviations

[0070] AA=acrylic acid

[0071] BA=butyl acrylate

[0072] MMA=methyl methacrylate

[0073] AN=acrylonitrile

[0074] EHA=2-ethylhexyl acrylate

[0075] DI water=deionized water

EXAMPLES AND COMPARATIVE EXAMPLES

[0076] Preparation of corrosion inhibiting compositions.

Example 1

[0077] Synthesis of A.

[0078] A mixture of 5 g succinic anhydride (0.05 mole) and 6.3 g1-(3-aminipropyl)imidazole (API, 0.05 mole) is heated under reflux in 40g of xylenes for 4 hours. Xylene is removed under reduced pressure, andthe crude product is dissolved in chloroform and washed with 50 mL of0.1% HCl. The chloroform layer is separated, dried with magnesiumsulfate and the chloroform is removed under reduced pressure to give A.¹H NMR in CDCl₃: δ 2.0(m,2H, —CH₂—CH₂—CH₂—), 2.7(s,4H, (CH₂—CO)₂═N—),3.6 (t,2H, -CH₂—N═(CO—CH₂)₂), 4.0(t, 2H, —CH₂-Imidazole), 7.0,7.2,7.6(s,1H, imidazole ring).

Example 2

[0079] Synthesis of B.

[0080] To 5 g of 2-octylsuccinic anhydride in 90 ml of toluene at 45° C.is added a solution of 3.2 g of API in 15 mL toluene. The reactionmixture is heated under reflux for 18 h. The toluene is removed underreduced pressure and the crude product is purified by liquidchromatography to give4.5g of B.

Example 3

[0081] Preparation of polymer containing succinic anhydride anddiisobutyl groups (P1).

[0082] A 1.8 L reactor was charged with 150.8 g of maleic anhydrideflakes, 485 g of dry reagent grade xylenes, 179.4 g diisobutylene and0.3 g of p-toluene sulfonic acid. The reactor was sealed. It was flushedwith nitrogen and a vacuum of −15 psig. was established. Heating to 160°C. was started and the initiator feed was prepared by dissolving 27.5 gof di-t-butylperoxide in 90 g of xylenes. When the reactor temperaturehad reached 160° C. the initiator solution was fed for 15 minutes at 2g/min. Heating is stopped and the reaction is exothermic to 175° C. and32 psig. The remaining initiator solution is added at 1 g/min for 85min. During this time the reactor is maintained at 175-180° C. withstirring at 160 rpm. After the initiator feed is the heating iscontinued for 30 min. The reaction mixture is cooled and the reactor isdrained at room temperature and pressure. This procedure gives 928 g ofsolution containing 35.2% solids. This solution (P1) is used for thefunctionalization process.

Example 4

[0083] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of C-1 andC-2.

[0084] To 20 g P1 is added slowly 5 g of API followed by 20 mL o-xylene.The reaction mixture is heated under reflux for 4 h and then allowed tocool to room temperature. The o-xylene layer is decanted and theo-xylene is removed under reduced pressure to give 1.5 g of C-1. Theresidue is dissolved in 50 mL acetone. The acetone and residual o-xyleneis removed under reduced pressure to give 12 g of C-2.

Example 5

[0085] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of D.

[0086] To a solution of 30 g of P1 is added 70 g of xylene. The solutionis heated to 80° C. and 1-(3-aminipropyl)imidazole (4.64 g) is addeddropwise. The reaction mixture is then heated under reflux for 4 hoursand the water removed by a Dean and Stark condenser. After cooling thexylene is removed under reduced pressure at 70° C. To the residue in theflask is added methanol and the methanol is removed under reducedpressure at 65° C. To the residue in the flask is added 40 g of acetoneis and the acetone is removed under reduced pressure at 60° C. toconstant weight to afford the product D.

Example 6

[0087] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of E and F.

[0088] To a mixture of 15 g of a solution P1 (45% solid) and 15 mL ofxylene, a mixture of 3.38 g of API and 0.183 g ethanolamine is addedslowly. The reaction is heated under reflux for 4 hours. It is cooled toroom temperature. The xylene layer is decanted, and the xylene isremoved under reduced pressure to obtain sample E. The precipitateremaining in the flask is dried under reduced pressure to obtain theproduct F.

Example 7

[0089] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of G and H.

[0090] To a mixture of 10 g of a solution P1 (45% solid) and 15 mL ofxylene, a mixture of 2.25 g of API and 0.298 g triethylene glycolmonoamine is added slowly. The reaction is heated under reflux for 4hours. It is cooled to room temperature. The xylene layer is decanted,and the xylene is removed under reduced pressure to obtain sample G. Theprecipitate remaining in the flask is dried under reduced pressure toobtain the product H.

Example 8

[0091] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of I and J.

[0092] To a solution of 11.1 g of P1 (45% solids) and 75 mL of xylene isadded 1.5 g of API, 1.1 g of P-alanine and 1.3 g of1,4-diazabicyclo[5.4.0]undec-7-ene and the mixture heated under refluxfor 4 hours. The mixture is cooled to room temperature. The xylene layeris decanted, and the xylene is removed under reduced pressure to obtainsample I. Methanol is added to the oil in the flask and the solutionfiltered. The methanol is removed under reduced pressure to give J.

Example 9

[0093] Functionalization of polymers containing succinic anhydride anddiisobutyl groups with 1-(3-aminipropyl)imidazole-synthesis of K and L.

[0094] To a solution of 11.1 g of P1 (45% solids) and 70 mL of xylene,1.5 g of API is added slowly and the reaction mixture heated underreflux for 4 hours, then cooled to room temperature. The xylene layer isdecanted, and the xylene is removed under reduced pressure to obtainsample K. Methanol is added to the oil in the flask and the solutionfiltered. The methanol is removed under reduced pressure to give L.

Example 10

[0095] Preparation of polymer containing succinic anhydride groups (P2).

[0096] To a 1-liter, 4-neck flask equipped with mechanical stirrer, areflux condenser topped with nitrogen inlet, and a thermocouple, wasadded 200 g of maleic anhydride and 200 g of technical grade xylenes.After flushing the reactor with an inert gas, the contents are heated to60° C. to dissolve the maleic anhydride and then 1.00 g of n-octylamine(NOA) is added. The stirred reactor contents are heated to reflux(140-145° C.) and 20.0 g of di-t-butylperoxide (DBP) in 167 g of xylenesis gradually added over two hours. The solution was maintained underreflux for two hours. The reactor is modified for vacuum distillationand xylenes are distilled off to obtain a solution of P2 at the desiredconcentration.

Example 11

[0097] Functionalization of P2-synthesis of M.

[0098] To 6 g of P2 in 90 g xylenes is slowly added 5.35 g of API. Thereaction is heated under reflux for 4 hours -and the allowed to cool toroom temperature. The xylene is removed under reduced pressure to obtainM.

Example 12

[0099] Functionalization of P2-synthesis of N.

[0100] To 6.04 g of P2 in 90 g xylene, 1.74 g of 3-methyl-1-butylamineis added slowly at room temperature, and the reaction mixture is heatedunder reflux for 1 h and cooled to 100° C. and 2.5 g API is slowly addedand the reaction mixture is again heated under reflux for 2 h. Xylene isremoved under reduced pressure to obtain the final product N.

Example 13

[0101] Functionalization of P2-synthesis of O.

[0102] To 7.2 g of P2 in 90 g xylene, 2.02g of 2-methyl-1-pentylamine isadded slowly into the solution at room temperature, then reactionmixture is heated under reflux for 2 h. The reaction mixture is cooleddown to 100° C., and 2.5 g of API is added slowly into the reactionmixture and it is heated under reflux for 2 h. Xylene is removed underreduced pressure to obtain final product sample O.

Example 14

[0103] Functionalization of P2-synthesis of P.

[0104] To 20 g of P2 in 80 g xylenes is slowly added 5.86 g ofn-octylamine. The reaction mixture is heated under reflux for 2 h thencooled down to 100° C. and 11.3 g of API is slowly added. The reactionis then heated under reflux for an additional 2 h, then cooled and thexylene is removed under reduced pressure to give P.

Example 15

[0105] Functionalization of P2-synthesis of Q

[0106] To a solution of 80 g of P2 in 80 g dioxane heated to 60 ° C. isslowly added a solution of 26.2 g of API in 25 g. of dioxane. Aftercooling, 80 g of water is added to dissolve the solids. The resultingsolution is concentrated to 50% solids to give Q.

Example 16

[0107] Functionalization of P2-synthesis of R.

[0108] A solution of 50 g of P2 in 40 g ethanol is hydrolyzed with 31.6g of a 50% ethanolic solution of NaOH. After adjusting the pH to 6.3, 20g of API is added and the reaction mixture heated under reflux for 20 h.After cooling the reaction mixture is concentrated and 158 g of water isadded to obtain R as a 47% aqueous solution.

Example 17

[0109] Functionalization of Pl-synthesis of S.

[0110] To a solution of 10.5 g P1 and 30 mL xylene at room temperatureis slowly added 2.6 g of 3-(aminomethyl)-pyridine. The reaction mixtureis heated under reflux for 4 h and allowed to cool to room temperature.The xylene is removed under reduced pressure to give 8.4 g of S.

Example 18

[0111] Functionalization of P1 at room temperature-synthesis of T.

[0112] To a solution of 7.3 g of P1 in ethylbenzene at 50° C. is added4.4 g of API. The reaction mixture is heated under reflux for 2 h. Thesolvent is removed under reduced pressure and the solids washed withethylbenzene to give 5.4 g of T.

Example 19

[0113] Functionalization of P1 at room temperature-synthesis of U.

[0114] To a solution of 20 g of P1 in 75 g of dioxane is slowly added asolution of 5 g API (0.04 moles) in 35 g of dioxane over 90 minutes. Thereaction mixture is heated to 60° C. for 15 minutes and cooled to roomtemperature. The solid is filtered off and washed with acetone, thendried in a vacuum oven to afford U.

Example 20

[0115] Functionalization of a poly(maleic anhydride-limonene) withAPI-synthesis of V.

[0116] To a solution of 1.5 g of the polymer poly(maleicanhydride-limonene) in 50 mL acetone is added 0.8 g of API. The reactionmixture was stirred for 4 h. The acetone was removed under reducedpressure to give V as a white solid.

Example 21

[0117] Functionalization of poly(maleic anhydride-alt-1-octadecene) withAPI-synthesis of W.

[0118] To a solution of 5.0 g of the polymer poly(maleicanhydride-alt-1-octadecene) (Aldrich) in 50 mL xylene at roomtemperature is slowly added 1.8 g of API. The reaction mixture is heatedunder reflux for 2 h and the water collected in a Dean and Starkcondenser. The xylene is removed under reduced pressure to give 6.4 g ofW.

Example 22

[0119] Functionalization of poly(maleic anhydride-alt-1-tetradecene)with API-synthesis of X.

[0120] To a solution of 10.0 g of the polymer poly(maleicanhydride-alt-1-tetradecene) (Aldrich) in 50 mL xylene at roomtemperature is slowly added 3.8 g of API. The reaction mixture is heatedunder reflux for 2 h and the water collected in a Dean and Starkcondenser. The xylene is removed under reduced pressure to give 13 g ofX.

Example 23

[0121] Preparation of polymer containing maleic anhydride and vinylacetate groups (P3).

[0122] A 4-neck round bottom flask containing 220 g of toluene is heatedto 75° C. and 6.3 g of maleic anhydride and 0.46 g of Lupersol-11 isadded. The solution is heated to 85° C. and a solution of 25.4 g ofmaleic anhydride, 28.5 g vinyl acetate, and 2.64 g of Lupersol-11 isadded over 2 h. After the addition is complete the reaction mixture iskept at 85° C. for 1 h. A solution of 0.5 g of Lupersol-11 in 2 gtoluene is added and the heating continued for an additional 1 h. Thereaction is cooled to give a solution of P3 containing 19.4% solids.

Example 24

[0123] Functionalization of poly(maleic anhydride-alt-vinylacetate) withAPI-synthesis of Y.

[0124] To 16.5 g of P3 (19.4% solids) in a 300 mL 3-neck round bottomflask is added 20 g of toluene. The reaction mixture is then heated to50° C. and 1.3 g of API in 10 g of toluene is added slowly. The reactionmixture is then heated under reflux for 16 h. The reaction is cooled andthe toluene decanted off. The solid residue is dried under vacuum togive Y.

Example 25

[0125] Functionalization of poly(styrene-maleic anhydride) withAPI-synthesis of Z.

[0126] To a solution of 10 g of SMA-1000 in 60 g Dioxane at 60° C., isadded slowly 6.2 g of API. The reaction mixture is heated under refluxfor 30 minutes, and all the dioxane is removed by distillation. 60 g offresh dioxane is added and the reaction mixture is heated under refluxfor 10 minutes. The reaction is cooled to room temperature. Theprecipitate is filtered, and it is dried in a vacuum oven at 75° C. for3h. Any excess API is removed from the solid by washing with acetone togive 16 g of Z.

Example 26

[0127] Functionalization of poly(maleic anhydride-methylvinylether) withAPI-synthesis of AA.

[0128] To a mixture of 10 g of the polymer poly(maleicanhydride-methylvinylether) (Gantrez AN-119) and 90 g dimethylformamide(DMF) is slowly added 12 g of API. The reaction mixture is heated underreflux for 4 hours, and the DMF is removed under reduced pressure. Thecrude product is dissolved in 500 mL of methanol. The methanol solutionis washed with 80 g Amberlyst-15 resin. The solvents are removed underreduced pressure to give 10 g of AA.

Example 27

[0129] Functionalization of poly(maleic anhydride-butylvinylether) withAPI-synthesis of BB.

[0130] To a solution of 4.95 g of the polymer poly(maleicanhydride-butylvinylether) in 45 g o-xylene is slowly added 3.125 g ofAPI. The reaction is heated under reflux for 4 h, and then the o-xyleneis removed under reduced pressure to obtain 7.4 g of BB.

Example 28

[0131] Functionalization of poly(maleic anhydride-methoxyethylvinylether) with API-synthesis of CC.

[0132] To a solution of 10 g of the polymer poly(maleicanhydride-methoxyethylvinylether) in 90 g DMF is slowly added 9.4 g API.The reaction mixture is heated under reflux for 4 h. The DMF is removedunder reduced pressure. The crude product is dissolved in 20 mL ofmethanol and the product is precipitated by adding 500 mL of diethylether. The precipitate is dissolved into 500 mL methanol, and themethanol solution is washed with Amberlyst-15 to remove unreacted API.The methanol is removed under reduced pressure to give 15 g of CC.

Example 29

[0133] Functionalization of poly(maleic anhydride-vinylacetate) withAPI-synthesis of DD.

[0134] Into a 300 mL 3-neck round bottom flask is introduced 62 g (0.052mole) of ethoxylated P3. To this is added 30 g of toluene and thereaction mixture heated to 55° C. A solution of 5.9 g of API in 10 g ofethanol is then slowly added. After the addition is complete thereaction mixture is heated under reflux for 26 h. Upon cooling, solidsseparated out. The solvent was decanted off and the residue was dried toobtain DD.

Example 30

[0135] Functionalization of poly(styrene-maleic anhydride) withAPI-synthesis of EE.

[0136] To a solution of 50 g SMA-1000 in 100 g of acetonitrile at 55° C.is added 40 g of an ethanol/water (1:1) mixture and the pH is adjustedto >5 with aqueous NaOH. To this mixture is added 20 g of API. Thereaction mixture is heated under reflux for 15 h. Distillation iscarried out to remove solvent. This affords EE as an aqueous solution.

Example 31

[0137] Synthesis of FF.

[0138] Separate solutions of 0.3 g of Lubrizol-1 in 15 mL isopropanol(initiator solution) and 5 g 1-(4′-vinylbenzyl)imidazole in 12 g acrylicacid (monomer solution) are prepared. To 17 mL isopropanol at 80° C.,the initiator solution is added at 10mL/hr. Simultaneously the monomersolution is added at 20 mL/hr. Just before the additions are complete,0.15 g of Lubrizol-11 is added into the reaction mixture and thereaction is held at 80° C. for 35 min. and then allowed to cool to roomtemperature. The precipitate is washed with 250 mL isopropanol to giveFF.

Example 32

[0139] Synthesis of poly(91.3 parts acrylic acid -8.7 parts1-acryloylbenzotriazole) GG.

[0140] Separate solutions of 0.4 g of Lubrizol-11 in 20 mL isopropanol(initiator solution) and 17 g 1-acrylobenzotriazole in 73.6 g acrylicacid (monomer solution) are prepared. To 100 mL isopropanol at 80° C.,the initiator solution is added at 10 mL/hr. Simultaneously the monomersolution is added at 24 mL/hr. Just before the additions are complete,0.15 g of Lubrizol-11 is added into the reaction mixture and thereaction is held at 80° C. for 35 minutes and then allowed to cool toroom temperature. The isopropanol is removed under reduced pressure togive GG.

Example 33

[0141] Synthesis of a copolymer of acrylic acid and1-(3-(2-hydroxypropylallylether))benzotriazole HH.

[0142] To a solution of 26 g of 1-(3-(2-hydroxypropylallylether)) in 125g isopropanol at 82° C. is added a solution of acrylic acid andLupersol-11 over 2 hours with the temperature maintained at 84° C. Afterthe addition is complete, the reaction is heated for 2 h and water isadded and the pH is adjusted to 5.2. The isopropanol-water azeotrope isdistilled off to give HH as an aqueous solution containing 36% activematerial.

Example 34

[0143] Synthesis of II.

[0144] Fifty grams of xylene is charged in a reactor followed by 9.8 g(0.1 moles) of maleic anhydride. The mixture is heated to 125° C. Asolution of 10.8 g (0.1 moles) of allylimidazole in 10 g of xylene and asolution of 0.4 g of Lubrizol-11 in 20 g of xylene are simultaneouslyfed to the reactor for 1 h. After the addition is complete, the heatingis continued for 30 minutes. The reaction mixture is cooled to roomtemperature and the solvent is removed under reduced pressure to giveII.

Example 35

[0145] Synthesis of JJ.

[0146] To 135 g of xylenes at 95° C. is fed a mixture of di-isobutylene(40%), ethyl acrylate (20%), and vinylimidazole (40%) in xylenescontaining 2.5% AIBN as the initiator. After the feed (2.5 h) thereaction is heated for 30 minutes. After cooling the solid polymer isprecipitated out by adding ether. The solid is then hydrolyzed withconcentrated HCl. After distillation, JJ is obtained as a clearsolution.

Example 36

[0147] Synthesis KK.

[0148] Butyl acrylate polymer (Mw/Mn=2370/1250; 51.2 g) with terminalunsaturation is charged to a 100 mL 3-neck reactor flask and 13.6 g ofimidazole (0.2 moles) is slowly added at room temperature. The reactionmixture is heated to 120° C. for 2 hours and cooled to room temperature.Water is added followed by diethyl ether to remove excess imidazole. Thediethyl ether layer is separated and filtered and the ether removedunder reduced pressure to give KK.

Example 37

[0149] Synthesis of LL.

[0150] To a solution of 20 g (0.156 moles) of butyl acrylate polymer(Mw/Mn=2370/1250) in 20 g of acetone is slowly added 9.8 g of API (0.078moles) for a period of 1 hour. After the addition is complete, themixture is stirred for 1 hour. Removal of solvent under reduced pressureaffords LL.

Example 38

[0151] Synthesis of MM.

[0152] A mixture of 17 g (0.03 moles) of acrylic acidtbutyl acrylatecopolymer and 1.12 g of API is placed in a Parr bomb reactor. The bombis heated at 180° C. for 4 h. The reaction mixture is then dialyzed witha YM-2 filter to remove the unreacted API to afford MM.

[0153] Corrosion Resistance Testing

[0154] The following procedure was utilized to determine the corrosionresistance of the polymer compositions of the invention under conditionsof chlorination. This test places emphasis on the ability of thecorrosion inhibiting polymer compositions to resist penetration ofchlorine through the adsorbed film on a copper surface.

[0155] Formulation stock solution:

[0156] A stock solution was prepared containing 1000 ppm of phosphoricacid (as PO₄ ³⁻, 1.21 g of 85% H₃PO₄), 625 ppm of1-hydroxyethylidene-1,1-disphosphonic acid (as PO₄ ³⁻, 1.13 g of 60%HEDP, Dequest® 2010, Solutia) and 625 ppm of Acumer® 2000 copolymersupplied at 39.5% actives by Rohm and Haas Company (1.58 g). To completethe stock solution, water was added to the mixture to afford a totalweight of 998 g. The pH was adjusted to 10.5 and then 1000 ppmtetrapotassium pyrophosphate (as PO₄ ³⁻, 1.74 g of TKPP) was added. ThepH of the final mixture was adjusted to 11.0.

[0157] Polymer stock solution:

[0158] Each polymer was prepared as 1000 ppm (as actives) in anappropriate solvent (water, methanol or isopropanol).

[0159] Preparation of a test solution:

[0160] To a container was added the following:

[0161] (a) 125 mL of an aqueous solution containing 500 ppm NaCl, 200ppm CaCl₂ (as CaCO₃), 100 ppm MgCl₂ (as CaCO₃), 400 ppm total alkalinity(as CaCO₃), adjusting the solution to pH 7.0;

[0162] (b) 1 mL of formulation stock solution; and

[0163] (c) 0.38 g of polymer stock solution (resulting in 3 ppm actives)

[0164] wherein the solution is maintained at pH 7.0.

[0165] Preparation of test apparatus:

[0166] Stainless steel reference electrode-sand with 600 grit SiC paper,rinse with water, rinse with isopropanol, rinse with water, towel dry.

[0167] 18 gauge copper working electrode-sand with 600 grit SiC paper,rinse with water, rinse with isopropanol, rinse with water, rinse withacetone then air dry.

[0168] Two stainless steel wires and one copper wire were inserted intothe container containing 125 mL of test solution, anchoring the wiresthrough a lid on top of the container. The copper wire is bent into aloop so that the volume/surface area of water to copper is 264 mL/in².The test solution was stirred at 300 rpm at room temperature for 18 h.After 18 h, 5 ppm NaOCl was added (as Cl₂). After 30 minutes, corrosionrate was measured as mil per year (mpy) using an EG&G Princeton AppliedResearch

[0169] Potentiostat/Galvanostat Model 273.

[0170] For test without chlorine, the above procedure was used with thefollowing conditions substituted where appropriate:

[0171] NaCl (1000 ppm), Ca/Mg (100 ppm/50 ppm as CaCO₃), volume/surfacearea 492 mL/in², 4 h polymer film formation time (unstirred). TABLE ICORROSION INHIBITING COMPOSITIONS AND COMPARATIVE EXAMPLES mpy mpy (3ppm) Example Sample (3 ppm) with NaOCl Comparative None 3.42 3.09Comparative Cobratec 0.05 1.24 TT-100 PMC Comparative Cobratec 0.02 2.1699 PMC  1 A — 1.70  2 B — 1.88  4 C-1 0.16 0.34 C-2 0.42 0.59  5 D —0.31  6 E 0.85 F 1.16  7 G — 0.42 H — 1.33  8 I — 0.36 J — 0.54  9 K —0.34 L — 1.00 11 M — 0.84 12 N — 0.50 13 O — 0.37 14 P — 0.15 15 Q —2.06 16 R — 1.16 17 S — 0.98 18 T — 1.14 19 U — 1.10 20 V — 1.95 21 W —2.37 22 X — 4.83 24 Y — 2.70 25 Z — 2.72 26 AA — 2.04 27 BB — 2.27 28 CC— 1.08 29 DD — 2.04 30 EE — 1.24 31 FF 0.44 2.36 32 GG 0.63 2.83 33 HH —2.70 34 II — 2.61 35 JJ — 2.49 36 KK 0.64 0.97 37 LL — 4.30 38 MM — 1.39

[0172] As Table I shows, the best performance in terms of corrosionresistance and chlorine resistance was obtained for several classes ofpolymers. A copolymer of maleic anhydride and diisobutylene postfunctionalized with aminopropyl imidazole (Examples 4 and 5) performedbetter than TTA, BZT with regard to chlorine resistance (Comparativeexamples 1 and 2) and favorably with regard to corrosion rate. Polymersof formula Ill-V (Examples 6-9, 12-14) performed better than TTA, BZTwith regard to chlorine resistance. Overall, most of the examples werecomparable to TTA and BZT in terms of chlorine resistance, confirmingthat they are attractive alternatives to TTA and BZT.

What is claimed is:
 1. A process for inhibiting corrosion of metalliccomponents in contact with an aqueous system comprising the step ofadding to the system an effective amount of one or more polymerscomprising: i) at least one repeating unit selected from afunctionalized imide component of Formula Ia, a functionalized amidecomponent of Formula Ib and combinations of Ia and Ib:

wherein n is 0 or 1; R and R₁ are independently selected from the groupconsisting of hydrogen, methyl, and C₂-C₄ alkyl; R₂ is selected from thegroup consisting of C₁-C₈ branched and straight chain alkyl groups,C₂-C₈ branched and straight chain alkenyl groups, C₃-C₈ cyclic alkylgroups, C₆-C₁₀ aromatic groups, C₂-C₄ alkylene oxide groups andpoly(C₂-C₄ alkylene)m oxides wherein m=2-20; a pendant heterocyclecomprising unsaturated or aromatic heterocycles having one or morehetero atoms selected from the group N, O, S and combinations thereof,the pendant heterocycle chemically bonded to the R₂ group via a heteroatom which is part of the heterocycle or a carbon atom of theheterocycle; R₃ is selected from the group consisting of hydrogen,methyl, ethyl, C₃-C₁₈ branched and straight chain, alkyl and alkenylgroups; and R₄ is selected from the group consisting of H, CH₃, C₂H₅,C₆H₅ and C₃-C₁₈ branched and straight chain alkyl groups and C₃-C₁₈alkenyl groups; ii) at least one ethylenically unsaturated monomercomponent selected from maleic anhydride, itaconic anhydride,cyclohex-4-enyl tetrahydrophthalic anhydride, and monomers of FormulaII: Formula II CH(R5)=C(R6)(R7) wherein R₅ is selected from hydrogen,phenyl, methyl, ethyl, C₃-C₁₈ branched and straight chain alkyl andalkenyl groups; R₆ is independently selected from hydrogen, methyl,ethyl, phenyl, C₃-C₁₈ branched and straight chain alkyl and alkenylgroups, OR₈ and CH₂OR₈ groups wherein R₈ is acetate, glycidyl, methyl,ethyl, C₃-C₁₈ branched and straight chain alkyl and alkenyl groups, andgroups having the formula [CH₂CH(R_(a))O]_(m)R_(b) wherein R_(a) ishydrogen, methyl, ethyl, and phenyl, m is an integer from 1-20 and R_(b)is independently hydrogen, methyl, ethyl, phenyl and benzyl; and R₇ isindependently selected from H, CH₃, C₂H₅, CN, a COR₉ group wherein R₉ isOH, NH₂, OR₈ group wherein R₈ is a group described previously and aNR_(c)R_(d) group wherein R_(c) and R_(d) are the same group ordifferent groups, are parts of a 5-membered or 6-membered ring system,hydrogen, hydroxymethyl, methoxy methyl, ethyl and C₃-C₁₈ branched andstraight chain alkyl and alkenyl groups branched and straight chainalkyl and alkenyl groups; and iii) optionally one or more end groupsselected from initiator fragments, chain transfer fragments, solventfragments and combinations thereof.
 2. The process according to claim 1,wherein the weight average molecular weight of the polymer is from 400to 20,000 and the pH of the aqueous system is from 6 to
 10. 3. Theprocess according to claim 1, wherein the amount of polymer added to theaqueous system is from 1 to 500 ppm, based on the weight of the aqueoussystem.
 4. The process according to claim 1, wherein the polymer isadded to the aqueous system on a periodic or a continuous basis.
 5. Theprocess according to claim 1, wherein the polymer is added to theaqueous system as formulation with one or more additives selected fromthe group consisting biocidal compositions, corrosion inhibitorcompositions known in the art, scale inhibiting compositions,dispersants, defoamers, inert fluorescent tracers and combinationsthereof.
 6. The process according to claim 1, wherein the polymercomprises a functionalized imide component of Formula 1a selected fromsuccinimide, glutarimide and combinations thereof; wherein the pendantheterocycle is selected from the group consisting of imidazole,triazoles and their respective isomers, thiophene, pyrrole, oxazole,azoles, indazoles thiazoles and their respective isomers, pyrazole,substituted thiazoles and their respective isomers, tetrazole, pyridine,pyridazine, pyrimidine, pyrazine, and combinations thereof; and whereinthe ethylenically unsaturated monomer component is selected from thegroup consisting of maleic anhydride, itaconic anhydride,cyclohex-4-enyl tetrahydrophthalic anhydride, ethylene, propylene,butylene, isobutylene, di-isobutylene, propylene tetramer (C₁₂-C₁₄),propylene dimer trimer (C₁₈-C₂₂), 1-butene, 1-octene, 1-decene; styrene,(x-methyl styrene, hydroxy styrene, styrene sulfonic acid, butadiene;vinyl acetate, vinyl butyrate, vinyl esters, vinyl chloride, vinylidenechloride, stilbene, divinyl benzene, (meth)acrylic acid, C₃-C₁₈(meth)acrylate esters, C₃-C₁₈ (meth)acrylamides and (meth)acrylonitrile.7. The process according to claim 1 wherein one or more of the polymersis of formula III: (A)x(B)y(C)z wherein A is an optional end groupcomponent selected from initiator fragments, chain transfer fragments,solvent fragments and combinations thereof; wherein B is afunctionalized imide component of Formula Ia, a functionalized amidecomponent of Formula Ib and combinations of Ia and Ib; wherein C is anethylenically unsaturated monomer component selected from maleicanhydride, itaconic anhydride, cyclohex-4-enyl tetrahydrophthalicanhydride, and monomers of Formula II; and wherein x, y, z are integersvalues chosen such that (y+z)/x is greater than
 2. 8. The polymeraccording to claim 7 wherein A is selected from the group consisting ofdialkyl peroxides, alkyl hydroperoxides, n-dodecyl isopropyl alcohol,alkyl phosphonates, alkyl phosphites, aryl phosphinic acids, alkylphosphinic acids, hypophosphites, aldehydes, formates, toluene, xylenes,C₉-C₁₀ alkylaromatics, and Aromatic 100; wherein the pendant heterocycleattached to B is selected from the group consisting of imidazole,triazoles and their respective isomers, thiophene, pyrrole, oxazole,azoles, indazoles, thiazoles and their respective isomers, pyrazole,substituted thiazoles and their respective isomers, tetrazole, pyridine,pyridazine, pyrimidine, pyrazine, and combinations thereof; and whereinC is selected from the group consisting of maleic anhydride, itaconicanhydride, cyclohex-4-enyl tetrahydrophthalic anhydride, ethylene,propylene, butylene, isobutylene, di-isobutylene, propylene tetramer(C₁₂-C₁₄), propylene dimer trimer (C₁₈-C₂₂), 1-butene, 1-octene,1-decene; styrene, α-methyl styrene, hydroxy styrene, styrene sulfonicacid, butadiene; vinyl acetate, vinyl butyrate, vinyl esters, vinylchloride, vinylidene chloride, stilbene, divinyl benzene, (meth)acrylicacid, C₃-C₁₈ (meth)acrylate esters, C₃-C₁₈ (meth)acrylamides and(meth)acrylonitrile.
 9. The process according to claim 1 wherein one ormore of the polymers is of formula IV: Formula IV (A)x(B)y(B′)z whereinA is an end group selected from initiators fragments, chain transferfragments, solvent fragments and combinations thereof, wherein B is afunctionalized imide component of Formula Ia selected from succinimide,glutarimide and combinations thereof; wherein B′ includes at least oneunit selected from a functionalized imide component or a functionalizedamide component selected from succinimide, glutarimide and combinationsthereof, wherein the nitrogen atom of each component of B′ is chemicallybonded to a group selected from C₁-C₁₈ branched or straight chain alkyl,C₁-C₁₈ alkyl or alkenyl substituted aryl, which is in turn chemicallybonded to a pendant functional group selected from an amine group, amidegroup, carboxylic acid group, alcohol group or a group having theformula [CH₂CH(R_(a))O]_(m)R_(a) wherein R_(b) is hydrogen, methyl,ethyl, and phenyl, m is an integer from 2-20 and R_(b) is independentlyhydrogen, methyl, ethyl, phenyl and benzyl; and wherein x, y, z areintegers values chosen such that (y+z)/x is greater than
 2. 10. Theprocess according to claim 9 wherein the group attached to B′ is anC₁-C₁₈ branched or straight chain alkyl amine and the pendantheterocycle attached to B is selected from the group consisting ofimidazole, triazoles and their respective isomers, thiophene, pyrrole,oxazole, azoles, indazoles, thiazoles and their respective isomers,pyrazole, substituted thiazoles and their respective isomers, tetrazole,pyridine, pyridazine, pyrimidine, pyrazine, and combinations thereof.